If your adding long tube headers to your 79-93 5.0 Mustang you'll need to upgrade your mid pipe to a shorty style for proper fitment. BBK's catted shorty x pipe features their unique die stamped performance Xtracter center X section to ensure great sound and performance gains. They use aluminized, 2.5" diameter tubing that is mandrel bent for consistent performance. The high flow cats ensure your vehicle remains 49 state emissions legal. (not legal for use in the state of California)